Set perf_dashboard_machine_group property on GPU.FYI builders

This is the proper configuration in order to upload data to perf
dashboard in LUCI world per bit.ly/perf-dashboard-machine-group

Bug: 1126174
Change-Id: I7dee106c574a94db027c6079012dedab944998f1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2399441
Auto-Submit: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Garrett Beaty <gbeaty@chromium.org>
Reviewed-by: Garrett Beaty <gbeaty@chromium.org>
Cr-Commit-Position: refs/heads/master@{#805072}

infra/config/lib/ci.star

@@ -718,6 +718,9 @@ def gpu_fyi_builder(*, name, **kwargs):
         builder_group = "chromium.gpu.fyi",
         service_account =
             "chromium-ci-gpu-builder@chops-service-accounts.iam.gserviceaccount.com",
+        properties = {
+            "perf_dashboard_machine_group": "ChromiumGPUFYI",
+        },
         **kwargs
     )